Rapid switching between slow and fast light by frequency-modulated transient spectral hole-burning

Abstract

The generation of slow and fast light in the same transient hole-burning experiment by two laser-frequency modulation methods is reported. The schemes allow for rapid switching between slow and fast light on very short time scales. Experiments were carried out in the R1(±3/2) line of a pale green (0.04 wt. % Cr) emerald, Be3Al2Si6O18:Cr3+ in π polarization (E∥c) at 2.3 K in a low magnetic field B∥c of 12 mT. Maximum delays and advancements for a 115 ns Gaussian pulse were 65 and −25 ns, respectively, corresponding to group indices of 7.8·103 and −3·103. The present schemes point to possible applications in all-optical switches.